Box construction



Sept. 8, 1964 J. o. BURMAN BOX CONSTRUCTION Filed March 20, 1961 i 5 Sheets-Sheet l N J'nven tar, rfoseyk 0. u rm an,

A gym Sept-- 8 1964 J. o. BURMAN 3,147,880

Box CONSTRUCTION Filed March 20, 1961 3 Sheets-Sheet 2 v 46 Inl/en tor,

l Josejfz urman,

sept- 8, 1954 J. o. BURMAN 3,147,880

BOX CONSTRUCTION Filed March 20, 1961 3 Sheets-Sheet 5 111 ,l ,1111 1111, ,l 111 ,1111 1 ,l 1 l United States Patent O 3,147,880 BOX CQNSTRUCTION Joseph 0. Burman, Attleboro, Mass., assigner to Progressive Machinery Corp., Attleboro, Mass., a corporation of Massachusetts Filed Mar. 2G, 1961, Ser. No. 96,995 23 Claims. (Cl. 220-35) The present invention relates generally to a novel and improved box construction and is more particularly concerned with improvements in boxes of the type normally used for the shipment and display of jewelry and the like, which boxes usually comprise a base section and a cover section pivotally associated therewith, and spring means for resiliently maintaining the cover in either a completely closed or a completely open position.

The basic object of my invention is to overcome certain shortcomings which have been found to exist in spring loaded boxes of the general type above described. More specifically, in the conventional jewelry box-and it will be understood that although reference is made to jewelry boxes, the instant invention is not limited to such use-it is the normal procedure to pivotally connect the cover and base sections of the box by means of hinge plates which are secured to the rear walls of the sections. An arcuate leaf spring is connected to the hinge plates and extends therebetween for resiliently maintaining the box either in a completely closed or a completely open position. Thus it will be seen that boxes of this type require a separate hinge element and further require a separate assembly operation, namely, the attachment of the hinge plates to the box sections. Not only does this necessitate a separate assembly operation, but in addition, since the hinge plates must be assembled to the box sections after said sections have been covered with their outer ornamental liner, and since the usual procedure is to attach the hinge plates to the box by means of lugs which extend through the rear walls of the box sections and are clinched outwardly, it follows that said attaching lugs are clearly visible when looking at the rear of the box, thus detracting from the attractiveness and neatness of the box.

Accordingly, it is a primary object of my invention to provide a box construction wherein the base and cover sections may be pivotally associated with each other without the necessity of utilizing any separate hinge elements.

It is a further object of my invention to provide a box construction wherein the base and cover sections are pivotally associated with each other but are not physically interconnected, said sections being maintained in their pivotal relation solely by means of the spring element which resiliently maintains the box in either completely closed or completely open position.

Another object is the provision of a box construction of the character described wherein the base and cover sections are for the most part identical and interchangeable, whereupon said sections may be made from the same die.

Another problem which has existed in prior art boxes of the type under consideration is the fact that there is no way to adjust the tension of the spring means. Thus, if the spring is too weak, the box will not be resiliently maintained in closed position with sufficient force, and conversely, if the spring is too strong, the box will snap shut with too great a force. Furthermore, where the spring is too strong, the box will frequently buckle or distort due to the excessive force exerted bythe spring, thereby necessitating that the box be constructed of structurally strong material, or suciently reinforced, which would otherwise be unnecessary'.

It is therefore a further important object of my invention to provide a combination box and spring arrangement 3,147,88() Patented Sept. 8, 1964 ice wherein the tension of the spring may be easily and quickly adjusted.

Another object is the provision of a box and spring combination wherein the tension of the spring is adjustable, and wherein means are provided for maintaining the spring in its desired position of adjustment.

Another object of my invention is the provision of an adjustable spring which may easily be mounted to maintain the cover and base sections of a hingeless box in assembled relation.

A further object of my invention is the provision of a box and spring combination of the character described which is simple and economically feasible to manufacture, which is effective and durable in use, and which enables a box of highly pleasing appearance to be obtained.

Other objects, features and advantages of the invention will become apparent as the description thereof proceeds when considered in connection with the accompanying illustrative drawings.

In the drawings which illustrate the best modes presently contemplated by me for carrying out my invention:

FIG. 1 is a transverse section of a box embodying my invention, looking toward the rear inside surface thereof, with parts broken away for purposes of illustration;

FIG. 2 is a rear elevational view of the box shown in FIG. 1;

FIG. 3 is a fragmentary sectional View similar to FIG. 1, on a reduced scale, with the spring removed and with the rear walls of the base and cover sections separated from each other;

FIG. 4 is a fragmentary sectional View, on an enlarged scale, taken on line 4 4 of FIG. l;

FIG. 5 is a top plan view of the spring element which forms a part of my invention, with a portion thereof broken away for purposes of illustration;

FIG. 6 is a front elevational view of the spring member;

FIG. 7 is a bottom view thereof;

FIG. 8 is a front elevational View of a hinge plate which constitutes a modification of my invention;

FIG. 9 is a tranverse section of a box comprising the hinge plate of FIG. 8, looking toward the rear wall of said box;

FIG. 10 is a fragmentary section, on an enlarged scale, taken on line lil-1t) of FIG. 9;

FIGS. 11 through 15 illustrate sequentially the means by which the hinge plate of FIG. 8 is secured within the box shown in FIG. 9;

FIG. 16 is a top plan view of a modified spring construction, with a portion thereof broken away for purposes of illustration; and

FIG. 17 is a right-hand edge View of the spring shown in FIG. 16.

Referring now to the drawings, there is shown a box 1t) comprising a cover section 12 and a base section 14. Said cover section comprises a top wall 16, side walls 18, rear wall Ztl and a front wall (not shown). Said base section comprises a bottom wall 22, side walls 24, rear wall 26, and a front wall (not shown). Although the sections 12 and 14 may be constructed of any desired structural material, my invention is of particular adaptation and value in connection with boxes wherein the base and cover sections are metallic shells which are subsequently covered with any suitable inner and outer liners (not shown), such as leatherette or the like, in order to provide the box with a more attractive and luxurious appearance. It is once again emphasized, however, that the base and cover sections do not have to be metallic, but rather they could be cardboard or the like, with suitable reinforcement, particularly at the rear walls thereof.

As will be seen most clearly in FIG. 3, the lower edge of rear wall 20 is provided with a plurality of integral depending tabs 28, 30 and 32, it being noted that each of said tabs is offset inwardly as at 34 (FIG. 4) by a distance substantially equal to the thickness of wall 20. It will further be noted that the tabs 28, 3i) and 32 are spaced from each other by a distance substantially equal to the width of each tab, it being understood that each tab is of similar width, although center tab 30 is of greater length than outer tabs 28 and 32 for reasons hereinafter to be described. Rear wall 26 of base section 14 is provided with a plurality of integral, upwardly extending similar tabs 36, 38 and 40, said tabs also being inwardly offset as at 42. Here again it will be noted that center tab 38 is somewhat longer than the other two tabs, and it will further be seen that the tabs are spaced similar to the spacing of the tabs in rear wall 20, it being noted that each set of tabs is staggered with respect to the other whereby said tabs can interengage in the manner shown most clearly in FIGS. 1, 2 and 4. More specifically, when cover section 12 and base section 14 are positioned so that their edges are in abutting relation, the tabs of each section will extend toward the other section and along the inner surface of the rear wall thereof. At the same time, the edge portions of each rear wall intermediate the tabs will bear on the offset portions of the opposite rear wall. When the rear walls are so interengaged, the cover and base sections cannot be slid transversely with respect to each other due to the side-by-side engagement of the tabs of one section with those of the other. At the same time, the sections cannot move forwardly or rearwardly with respect to each other due to the engagement of the tabs along the inner surface of the rear wall of the opposlte section. Of course, at this point there is nothing to prevent the sections from being separated from each other in a vertical plane, or, expressed differently, in the plane of rear walls 20 and 26. In order to maintain the box sections in assembled relation, and at the same time, in order to provide resilient means for normally biasing the box to either a completely closed or a coinpletely open position, spring means 44 shown in detail in FIGS. 5 through 7 are provided.

Spring 44 is an arcuate leaf spring having an arcuate body portion 46 having inturned lips 48 at its opposite longitudinal edges. It is important to note .that said opposite longitudinal edges are angularly incllned with respect to each other whereby to define a wedge-shaped or divergent configuration. For reasons which will hereinafter become apparent, the convergent arcuate edge 50 of spring 44 is provided with opposed depressions as at 52. It will also be noted that spring 44 is preferably provided with a plurality of spaced slits 54 extending inwardly from the longitudinal edges of said spring.

Referring again to FIGS. 1 through 4, it will be seen that the rear wall of each section is provided with a series of integrally struck lugs S6, said lugs defining a d1- vergent trackway for receiving the inturned lips 48 of spring 44. More specifically, when the box sectlons are in abutting relation as illustrated in FIGS. 1, 2 and .4, each series of lugs defines a single trackway for receiving one of the inturned lips 48, it being understood that when the box sections are assembled to each other, the trackway defined by one series of lugs is spaced from the other trackway by a distance substantially equal to the width of spring 44. Thus, the spring 44 may be easily slid onto said trackways, and depending upon the degree of force with which the spring is wedged into position, the tension exerted by the spring will be varied. Thus, when viewing FIG. l, for example, the farther spring 44 is wedged to the left, the greater will be the spring tension exerted thereby. In order to malntam the spring in its desired position of adjustment, the lugs 56 at the convergent end of the trackway defined by said lugs are serrated as at 58, whereby when said spring is wedged into position, the depressions 52 will engage said serrations, as clearly shown in FIGS. 1 and 2, to maintain the spring in its position of desired adjustment. For purposes of strength and rigidity, the lugs 56 are preferably crowned or bowed as at 60.

Thus it will be seen that with the spring 44 mounted in its desired position as above described, the sections 12 and 14 will be maintained in assembled relation, but at the same time will be free to pivot with respect to each other to the position shown in dotted lines in FIG. 4. As is well known in the art, spring 44 will function to resiliently maintain the cover section in completely closed position and/or in its completely open position. Due to the fact that the base and cover sections are not actually connected to each other, but rather are maintained in assembled pivotal association solely by means of spring 44, it will be seen that if the cover section were to pivot open beyond a certain point, the two sections could and would become disengaged and disassembled. Accordingly, it is important to insure that the cover section cannot open excessively, and this is accomplished by engagement of spring 44 with the extremity of tab 38 as the box is swung open. Expressed differently, and as will be clearly seen in FIG. 4, as the cover section is swung open, the spring moves to the dotted-line position shown in FIG. 4 until it contacts the edge of tab 3S. When this contact is made, the cover section is incapable of further pivotal opening movement, and hence it will be seen that the length of tab 38 regulates the degree of opening movement of the box. It is for this reason that the tabs 30 and 38 are longer than the remaining tabs, it being understood that if the sections were reversed so that section 12 becomes the base section and section 14 the cover section, then tab 30 would engage the spring and function as the stop. In order to impart greater rigidity to these tabs so that they can withstand the pressure which is exerted on them by the spring when the box reaches its fully opened position, I prefer to slightly bow or crown them. It is desirable to have the remaining tabs shorter since this facilitates assembly of the spring by providing a greater degree of clearance as the spring is slid to its assembled posltion.

As will be seen most clearly in FIGS. 4 and 6, spring 44 is of constant height throughout its length. More specifically, the distance between the center of arcuate body portion 46 and the plane of inturned lips 48 remains constant throughout the length of the spring. This is to prevent the spring from extending excessively into the interior of the box, and at the same time, it has been found that this configuration enables better resilient control to be obtained. Also, this particular configuration enables the springs to be more easily handled when manufactured by automatic machinery, since there is less tendency for the springs to nest with each other, as would be the case if the height of the spring increased in proportion to the divergence of the longitudinal edges. The slits 54 are provided simply to impart a greater degree of flexibility to the spring, particularly where a relatively long spring is used, in order to insure that the spring will properly engage the lugs 56. The plurality of lugs 56 provided in each section results in greater structural rigidity than would be the case where one elongated lug is being provided in each rear wall. In addition, the wall portions between adjacent lugs provide stop portions for insuring that the lips 48 of spring 44 can never extend through the rear wall, as would be a distinct possibility if one elongated integrally struck lug were provided.

As hereinbefore mentioned, in normal use the metallic sections 12 and 14 will be lined with leatherette or the like, and it has been found that when the sections are so lined, there is a tendency for the lining to bunch slightly at the corners. Since bunching at the rear corners would obviously prevent the box from closing completely, the rear walls of each section are dimensioned anlass@ so that when in abutting engagement with each other, a clearance 62 will be provided around the remainder of the periphery of the box, which clearance insures that the box can always close completely after the outer lining has been applied.

It is also important to note that the base and cover sections are identical pieces which may be made from the same die, although when the lugs 56 are struck from the respective rear walls, the sections no longer are identical. By spacing the rear wall tabs olf center, it follows that when the sections are positioned for engagement with each other, the tabs will be staggered, as aforedescribed. By having cover and base sections which can be made from the same die, obvious manufacturing savings are realized, both from a time and iinancial standpoint.

Referring now to FIGS. 8 through 15, a modified form of my invention is illustrated and will now be described. In this form of my invention, a box 64 having base and cover sections 66 and 68, respectively, are hinged together by means of a conventional hinge 70 having hinge plates 72 and 74 pivotally associated with hinge pin 76 in a well-known manner. Thus it will be seen that in this form of my invention the box is not hingeless as was the case in the form illustrated in FIGS. 1 through 7. However, it Will be seen that the advantages derived from my so-called tapered spring are equally applicable to a hinged box.

Thus, it will be seen that hinge plate 72 is provided with a pair of integrally struck lugs 78, each of which is oppositely disposed to a similar pair of lugs 80 integrally struck from plate 74. It will be seen that each opposed pair of lugs 78 and 80 is angularly inclined with respect to each other in order to provide a divergent trackway, it being noted that the convergent end of each trackway is located adjacent the ends of the hinge. It will further be noted that the lugs are serrated, as at 82, at their convergent ends. In addition, a plurality of slitted tabs 84 are provided in each of the hinge plates.

A pair of springs 86 is provided and is adapted to be slidably received by trackways dened by each pair of opposed lugs. Spring 86 is identical to the aforedescribed spring 44 with the exception of the fact that the slits 54 are omitted, due to the fact that spring 86 is of shorter length, and hence said slits are not necessary. In any event, the longitudinal edges of spring 86 incline toward each other and are provided with inturned lips 88 which are adapted to Wedge onto the lugs 78 and 80 in the same manner as described in connection with the first embodiment of my invention. Each of the springs 36 is provided with a depressed portion 90 which cooperates with the serrations 82 to maintain the springs in their position of desired adjustment. Here again it will be seen that the degree to which the springs are Awedged onto the lugs will determine the tension exerted ,adjustable by simply varying the position of the springs.

By having the convergent ends of the springs outwardly disposed, the assembly of the springs onto the hinge plates is somewhat facilitated. Also, it will be understood that although in this embodiment of my invention I have utilized two separate springs at opposite ends of the hinge, the number of springs is in no way critical. More specifically, one spring could be centrally disposed on the hinge plate, or else two or more springs can be used. The width of the box and the hinge plates will normally determine the desirability of using more than one spring. By the same token, it will be understood that in the form of my invention illustrated in FIGS. 1 through 7, a pair of springs could be used similar to the arrangement shown in FIGS. 8 and 9.

It is of interest to note that in the form of my invention illustrated in FIGS. 8 and 9, i.e., where a pair of springs is provided, the base and cover sections are identical, even after lugs 78, 8@ are struck, and this is so whether hinge plates are used or whether the box is hingeless and said lugs are struck from the section rear wal s.

In FIGS. 11 through 15 a preferred form for mounting the hinge plates to box 64 is illustrated. In this form, the tabs 84 in the hinge plates are iirst bent upwardly as shown in FIG. 11. Then prongs 92 are integrally struck from the rear Walls of the box and are forced through the openings provided by the upwardly bent tabs S4, as illustrated in FIGS. 12 and 13. The prongs are then bent over and the tabs 84 forced downwardly thereagainst, as shown in FIGS. .14 and 15. It is important to note that the width of prings 92 is substantially less than that of the tabs 84 whereby to provide a certain degree of tolerance for any misalignment that may exist between the hinge plate tabs and the box prongs. It has been found that when the tabs are clinched over the prongs, as illustrated in FIGS. 14 and 15, the hinge plate will be held firmly in place, whereas if the tabs 84 were not provided, there would be a certain amount of undesirable play between the hinge plates and the box sections.

In FIGS. 16 and 17 a modified spring construction 94 is shown which, while not tapered like springs 44 and 86, nevertheless is constructed so as to cooperate with a divergent trackway in the same manner. As will be seen, spring 94 is provided with substantially parallel longitudinal edges, withan inturned lip 96 at each edge and a pair of depressed portions 98 at one of the arcuate edges. In order that the spring may be sufciently flexible so as to conform to the divergent trackway, a plurality of longitudinal slits 188 are provided, with at least one such slit extending from each arcuate edge. It will be understood that the spring 94 is adapted to cooperate with a divergent trackway formed by lugs identical to those hereinbefore illustrated and described. The longitudinal slits provide sufficient iexibility to the spring so that it can be wedged onto the divergent trackway, the exact position of the spring on the trackway determining the spring tension, exactly as in the previous forms of my invention. The depressed portions 98 cooperate with serrations on the spring retaining lugs to maintain the spring in its position of desired adjustment, as aforedescribed.

It will thus be seen that there has been provided in accordance with the instant invention a spring construction which readily enables the spring tension of jewelry boxes and the like to be quickly and easily adjusted, whether the box is a conventional hinged box, or whether it embodies my novel hingeless construction, as illustrated in FIGS. 1 through 7. While there is shown and described herein certain specific structure embodying the invention, it will be manifest to those skilled in the art that various modifications and rearrangements of the parts may be made without departing from the spirit and scope of the underlying inventive concept and that the same is not limited to the particular forms herein shown and described except insofar as indicated by -the scope of the appended claims.

What is claimed is:

1. A box comprising cover and base sections pivotally movable with respect to each other between an open and a closed position, spring means for resiliently maintaining said box in its said closed position, said spring means simultaneously maintaining said cover and base sections assembled to each other, said sections being otherwise disconnected, said spring means comprising an arcuate leaf spring having inturned lips at its opposite longitudinal edges, said base and cover sections each having inwardly extending lugs for receiving said inturned lips, said lugs defining a divergent path with each other, said spring being tapered along its longitudinal edges to conform to said lugs and so that it may easily be slid thereon, whereby the tension of said spring can be adjusted by varying its longitudinal position on said lugs.

2. A box comprising cover and base sections pivotally movable with respect to each other between an open and a closed position, spring means for resiliently maintaining said box in its said closed position, said spring means simultaneously maintaining said cover and base sections assembled to each other, said sections being otherwise disconnected, said spring means comprising an arcuate leaf spring having inturned lips at its opposite longitudinal edges, said base and cover sections each having inwardly extending lugs for receiving said inturned lips, said lugs defining a divergent path with each other, said spring having at least one longitudinally extending slit so that said spring is sufficiently flexible to enable it to conform to said divergent path, whereby when said spring is slid onto said lugs, the tension of said spring can be adjusted by varying its longitudinal position on said lugs.

3. A box comprising a base section having a bottom wall, front and rear Walls, and side walls, and a cover section having a top wall, front and rear walls, and side walls, said rear Walls having interengaging portions adjacent their edges whereby said cover and base may pivot with respect to each other between an open and a closed position, and spring means for resiliently maintaining said box in its said closed position, said spring means comprising at least one arcuate leaf spring having inturned lips at its opposite longitudinal edges, said rear walls each having inwardly extending lugs for receiving said inturned lips, whereby said spring maintains said cover and base sections assembled to each other, said sections being otherwise disconnected, said lugs deiining a divergent path with each other, said spring being tapered along its longitudinal edges to conform to said lugs and so that it may easily be slid thereon, whereby the tension of said spring can be adjusted by varying its longitudinal position on said lugs.

4. A box comprising a base section having a bottom wall, front and rear walls, and side walls, and a cover section having a top wall, front and rear walls, and side Walls, said rear walls having interengaging portions adjacent their edges whereby said cover and base may pivot with respect to each other between an open and a closed position, and spring means for resiliently maintaining said box in its said closed position, said spring means comprising at least one arcuate leaf spring having inturned lips at its opposite longitudinal edges, said rear walis each having inwardly extending lugs for receiving said inturned lips, whereby said spring maintains said cover and base sections assembled to each other, said sections being otherwise disconnected, said lugs defining a divergent path with each other, said spring having at least one longitudinally extending slit so that said spring is suiciently flexible to enable it to conform to said divergent path, whereby when said spring is slid onto said lugs, the tension of said spring can be adjusted by varying its longitudinal position on said lugs.

5. The box of claim 3 further characterized in that the height of said spring, as defined by the distance between the center of the spring arc and a plane defined by the spring longitudinal edges, is substantially constant throughout the length of the spring.

6. The box of claim 3 further characterized in that the spring is provided with a plurality of slits extending inwardly from the opposed longitudinal edges of said spring.

7. The box of claim 3 further characterized in that said lugs are integrally struck from said rear walls, each rear wall having a plurality of spaced lugs.

8. The box of claim 3 further characterized in that an edge portion of one of said lugs is serrated, and said spring is provided with a depressed edge portion for engaging said serrations, whereby to maintain said spring in its position of desired adjustment.

9. In a box having a base section and a cover section c hingedly associated therewith for movement between an open and a closed position, spring means for resiliently maintaining said cover in closed position, said spring means comprising an arcuate leaf spring having inturned lips at its opposed longitudinal edges, and a lug on each of said cover and base sections for receiving said spring lips, said lugs defining a divergent path with each other whereby when said spring is slid thereon, the tension of said spring may be adjusted by the degree of force with which said spring is wedged onto said lugs.

, 10. In a box having a base section and a cover section hingedly associated therewith for movement between an open and a closed position, spring means for resiliently maintaining said cover in closed position, said spring means comprising an arcuate leaf spring having inturned lips at its opposed longitudinal edges, said opposed edges being angulariy inclined with respect to each other whereby to define a taper, a lug on each of said cover and base sections for receiving said spring lips, said lugs defining a divergent path with each other whereby said spring may be slid thereon, the tension of said spring being adjustable by the degree of force with which said spring is wedged onto said lugs, and means for maintaining the spring in its position of desired adjustment.

ll. The box of claim 10 further characterized in that said maintaining means comprise serrations on an edge portion of one of said lugs, and a depressed edge portion on said spring adapted to engage and ride over said serrations as said spring is slidingly wedged onto said lugs.

l2. A box section comprising a base wall, front, side and rear walls, a plurality of spaced tabs extending from the edge of said rear wall, said tabs each being inwardly offset and then extending away from the base wall in a plane substantially parallel to that of said rear wall, said rear wall having at least one integrally struck, inwardly extending lug, said lug defining a track which is angularly inclined with respect to said rear wall edge.

13. The box section of claim 12 further characterized in that an edge portion of said lug is serrated.

14. The box section of claim 12 further characterized in that a plurality of spaced inwardly extending lugs are blanked from said rear wall, said lugs defining a straight, angular track.

15. The box section of claim 12 further characterized in that said tabs are of identical width and are spaced from each other a distance just slightly greater than said width.

16. A box comprising cover and base sections, hinge means pivotally interconnecting said sections, and spring means associated with said hinge means for resiliently maintaining said box in closed position, said spring means comprising an arcuate leaf spring having inturned lips along its opposed longitudinal edges, said hinge means having at least one pair of opposed lugs for slidably receiving said inturned lips, said lugs being angularly inclined toward each other whereby to define a divergent track, whereby the tension of said spring may be adjusted by the degree of force with which said spring is wedged onto said lugs.

17. The box of claim 16 further characterized in that two pairs of opposed lugs are provided, one adjacent each end of said hinge means, with the convergent end of each track outwardly disposed, and a spring for each pair of lugs.

18. The box of claim 16 further characterized in that said spring longitudinal edges incline toward each other to provide a tapered spring.

19. The box of claim 16 further characterized in that said spring longitudinal edges are substantially parallel, said spring having at least one longitudinal slit extending from one of the end edges thereof.

20. The box of claim 16 further characterized in that said hinge means comprise a pair of hinged plates, and

means securing one of said plates to one of said sections and the other of said plates to the other section, said means comprising prongs extending from said sections, openings in said plates for receiving said prongs, said openings being substantially larger than said prongs whereby to provide suiiicient assembly tolerance, and tabs extending from said plates adjacent said openings, said tabs being bendable into engagement with said prongs, whereby to maintain said hinge plates rigidly positioned with respect to said box.

21. A box comprising a base section having a bottom wall, front and rear walls, and side walls, and a cover section having a top wall, front and rear walls, and side walls, a plurality of spaced tabs on the edges of said rear walls, said tabs being offset inwardly and then extending away from their respective section in a plane substantially parallel to the plane of said rear walls, the tabs of one section being staggered with respect to the tabs of the other section whereby when said rear wall edges abut each other, the tabs of each rear wall extend adjacent the inner surface of the other rear wall, with the edge of each rear wall intermediate the tabs bearing on the offset prtions of the other rear wall so that said cover section may swing pivotally open about an axis dened by said abutting rear edges, and spring means resiliently maintaining said cover section in closed position, said spring means comprising a tapered, arcuate leaf spring having inturned lips at its opposite longitudinal edges, said opposite longitudinal edges converging toward each other, said rear walls each having inwardly extending lugs for slidably receiving said spring lips, said lugs deiining a divergent track whereby the tension of said spring may be adjusted by the degree of force with which said spring is wedged onto said lugs, said spring simultaneously functioning to maintain said sections pivotally assembled to each other, said sections being otherwise disconnected, the tabs which underlie said spring being of sufcient length so as to engage the spring when the box is opened to limit the extent to which said box can open.

22. The box of claim 21 further characterized in that the tabs which are not covered by the spring are of lesser length than those which underlie the spring.

23. A box comprising cover and base sections pivotally movable with respect to each other between an open and a closed position, spring means for resiliently maintaining said box in its said closed position, said spring means simultaneously maintaining said cover and base sections assembled to each other, said sections being otherwise disconnected, said spring means comprising an arcuate leaf spring having inturned lips at its opposed longitudinal edges, and a lug on each of said cover and base sections for receiving said spring lips, said lugs defining a divergent path with each other whereby when said spring is slid thereon, the tension of said spring may be adjusted by the degree of force with which said spring is wedged onto said lugs.

24. A box comprising cover and base sections pivotally movable with respect to each other between an open and a closed position, spring means for resiliently maintaining said box in its said closed position, said spring means comprising an arcuate leaf spring having inturned lips at its opposed longitudinal edges, said opposed edges being angularly inclined with respect to each other whereby to define a taper, and means on said base and cover sections for slidably receiving said spring lips, the tension of said spring being adjustable by the degree of force with which the spring is slidably wedged onto said means.

25. A box comprising a base section having a bottom wall, front and rear walls, and side walls, and a cover section having a top wall, front and rear walls, and side walls, said rear walls having interengaging portions adjacent their edges whereby said cover and base may pivot with respect to each other between an open and a closed position, and spring means for resiliently maintaining said box in its said closed position, said spring means simultaneously maintaining said cover and base sections assembled to each other, said sections being otherwise disconnected, said interengaging portions comprising a plurality of spaced tabs on the edges of said rear walls, said tabs being offset inwardly and then extending away from their respective section in a plane substantially parallel to the plane of said rear walls, the tabs of one section being staggered with respect to the tabs of the other section, whereby when said rear Wall edges abut each other, the tabs of each rear wall extend adjacent the inner surface of the other rear Wall, with the edge of each rear wall intermediate the tabs bearing on the otfset portions of the other rear wall, said spring means comprising an acruate leaf spring having inturned lips at its opposite longitudinal edges, said base and cover sections each having inwardly extending lugs for receiving said inturned lips, the tabs which underlie said spring being of sucient length so as to engage the spring when the box is opened to limit the extent to which said box can open.

26. In a spring for use in a box construction, an arcuate body portion having opposed longitudinal edges, said edges being angularly inclined with respect to each other to define a wedge-shaped conguration, and an inturned lip extending along each of said longitudinal edges, said arcuate body portion being of substantially constant height throughout the length of said spring.

27. The spring of claim 26 further characterized in that said spring is provided with a plurality of slits extending inwardly from each longitudinal edge.

28. The spring of claim 26 further characterized in that a depressed portion is provided at the arcuate edge of the convergent end of the spring.

References Cited in the le of this patent UNITED STATES PATENTS 92,715 Gardner July 20, 1869 2,014,951 Rathbun Sept. 17, 1935 2,506,789 Hyde May 9, 1950 

1. A BOX COMPRISING COVER AND BASE SECTIONS PIVOTALLY MOVABLE WITH RESPECT TO EACH OTHER BETWEEN AN OPEN AND A CLOSED POSITION, SPRING MENS FOR RESILIENTLY MAINTAINING SAID BOX IN ITS SAID CLOSED POSITION, SAID SPRING MEANS SIMULTANEOUSLY MAINTAINING SAID COVER AND BASE SECTIONS ASSEMBLED TO EACH OTHER, SAID SECTIONS BEING OTHERWISE DISCONNECTED, SAID SPRING MEANS COMPRISING AN ARCUATE LEAF SPRING HAVING INTURNED LIPS AT ITS OPPOSITE LONGITUDINAL EDGES, SAID BASE AND COVER SECTIONS EACH HAVING INWARDLY EXTENDING LUGS FOR RECEIVING SAID INTURNED LIPS, SAID LUGS DEFINING A DIVERGENT PATH WITH EACH OTHER, SAID SPRING BEING TAPERED ALONG ITS LONGITUDINAL EDGES TO CONFORM TO SAID LUGS AND SO THAT IT MAY EASILY BE SLID THEREON, WHEREBY THE TENSION OF SAID SPRING CAN BE ADJUSTED BY VARYING ITS LONGITUDINAL POSITION ON SAID LUGS. 